Providing information by radio transmission includes the steps of data generation and data transmission. The process of data transmission is typically separate from the process of data generation. When physically separate, a communication link delivers information from the data generating installation to the data transmission installation. In the case of time synchronous data, as provided in a time synchronous communication protocol, a predetermined transmission rate and a precise time of transmission is required. It is necessary, therefore, to provide real time synchronization of transmitted data to maintain proper system operation.
Flow control for time critical data presents additional system requirements. The data generating installation must provide a flow of data to the transmission installation at least as great as the transmission rate. If the data flow is insufficient, i.e. in the event of underflow, the transmission facility lacks data to transmit and fails to maintain system protocol. Providing an overflow of data, i.e., buffering large volumes of data at the transmission facility, is not desirable when system protocol calls for transmission as soon as possible following data generation.